In recent years, a hybrid vehicle equipped with an engine and a motor as a vehicle power source has attracted attention for the reasons of societal demands such as low fuel consumption and low exhaust emission. Such a hybrid vehicle includes, for example, a vehicle configured such that EV travelling for causing the vehicle to travel by power of a motor with an engine being stopped is performed to improve fuel economy. However, when the time for operating the engine to ensure an amount of heat for heating during, e.g., the wintertime, is increased, the fuel economy has a tendency to be lowered. The amount of heat for heating is an amount of heat of coolant water for the engine.
Thus, Patent Literature 1 describes the technique of mounting a heating device configured to heat coolant water in addition to an engine. In this technique, a heat pump and an exhaust heat recovery unit are provided at the heating device configured to heat the coolant water, and a rotation speed of a compressor of the heat pump is controlled based on a coolant water temperature, an exhaust gas temperature, and engine output to reduce power consumption of the heat pump.